scsi: target: Pass in cmd counter to use during cmd setup

Allow target_get_sess_cmd() users to pass in the cmd counter they want to
use. Right now we pass in the session's cmd counter but in a subsequent
commit iSCSI will switch from per session to per conn.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://lore.kernel.org/r/20230319015620.96006-4-michael.christie@oracle.com


Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>